For suppressing adhesion of a biological substance to medical instruments, equipment, etc., such as an artificial dialyzer, artificial organs, medical equipment, etc., various coating materials having a function of inhibiting adhesion of a biological substance have been proposed. Among these, it has been known a material of inhibiting adhesion of a biological substance by coating a polymer having an ethylene glycol chain at the side chain and, for example, in Patent Document 1, examples of coating a copolymer of 2-methoxyethyl acrylate onto nonwoven fabric such as a blood filter and a dialysis filter, etc., have been disclosed. Also, in Non-Patent Document 1, to impart a function of inhibiting adhesion of a biological substance to polysulfone (PSF) or polyether sulfone (PES), etc., which is used as a substrate for an artificial dialysis film, it has been disclosed that polyvinylpyrrolidone (PVP) having a hydrophilic property is coated thereon. However, while these materials have a function of inhibiting adhesion of a biological substance which is expected due to the effect of the hydrophilic property, etc., solubility of the polymer itself to water is suppressed and solubility in an alcohol or an organic solvent is heightened, elution of the coating film itself has been identified by the causes of washing with ethanol, etc., for sterilization, shear stress (shearing stress) to the coating film by a high viscosity biological substance, etc., and use for a long period of time, etc., and yet allergy, etc., due to the eluate is a matter of concern.
On the other hand, a material having a polymer material containing a cation and an anion at the side chain on the surface thereof has been known to have a function of preventing adsorption of a biological substance (protein, cell, etc.) by being maintained to electrically neutral at the surface thereof due to electrostatic balance. In addition, it has also been proposed a coating material using such a function, and various reports have been made on the fixation or immobilization method to glass or a polymer substrate, etc. For example, in Non-Patent Document 2, it has been reported that surface modification was accomplished by chemical adsorption with a glass substrate using a polymer obtained by copolymerizing 2-methacryloyloxyethyl phosphoryl choline (MPC) having a similar molecular structure to a phospholipid as a charge neutralization unit and 3-(trimethoxysilyl)propyl methacrylate having a silane coupling group. On the other hand, it has also been reported that onto a polymer substrate, a polymer into which butyl methacrylate has been copolymerized is to be fixed onto the substrate by aiming physical adsorption due to hydrophobic interaction. However, according to these methods, it is necessary to select a kind of the polymer depending on a kind of the substrate.
Also, in Patent Document 2, a coating film which is obtained from a film formed from a coating solution containing a polymer having a phosphate group by subjecting to heat treatment at 200 to 450° C. has been disclosed. To suppress elution of the coating film into an aqueous medium, it is necessary to carry out heat treatment at a high temperature of 200 to 450° C. after coating onto a substrate, so that a heating device such as an oven, a hot plate, etc., is necessary for the heat treatment. In addition, there was a problem that it could be difficultly applied to a substrate having low heat resistance such as a resin material, etc. Further, various polymers have been polymerized to manufacture a coating solution for forming a coating film, but in the Examples, polymerization reaction was carried out in ethanol, and polymerization reactivity in water was unclear.
Further, in Patent Document 3, there are disclosed a novel acrylic phosphate amine salt monomer (half salt) obtained by reacting an amine with an acrylic acidic phosphate monomer in the presence of water to selectively proceed an acid-base reaction and a method for manufacturing the same. The amine salt (half salt) has been disclosed to have a wide range of uses and usefulness in the field of a photosensitive resin as a monomer for providing rubber elasticity or a modifier of an oil-soluble substance, but it is unclear about polymerization reactivity of the amine salt (half salt) monomer itself in water, and a function of inhibiting adhesion of the obtained polymer to a biological substance. In addition, a used ratio of the above-mentioned acrylic acidic phosphate monomer in the whole used monomer at the time of polymerization in a polar solvent such as methanol, etc., is mainly around 5% to around 1% in many examples, and there is disclosed that if an amount is larger, the product is gelled.
Moreover, in Patent Document 4, a blood purifier having a hollow fiber film containing polyvinylpyrrolidone (PVP) has been disclosed, a mode diameter at the peak which is residing at the largest diameter in the particle diameter distribution measured by the dynamic light scattering method of the PVP in the hollow fiber has been disclosed to be 300 nm or less, and to coat the inside of the hollow fiber using the PVP coating liquid has been disclosed.